Advances in network communication and switching are moving ahead with great speed. The advent of optical network connections requires the evolution of network multiplexing and transmission technologies that can perform at high rates. Some of the technologies that assist in high performance include Dense Wavelength Division Multiplexing (DWDM). An advantage of DWDM is that many light waves carrying different data can be transmitted through the same fiber simultaneously. This parallel communication is very efficient since the same fiber can be used to transport many communication links.
The companies that build and operate the network backbone are called carriers and they define the network system requirements, which are ordinarily based on predicted user demand. Typical contemporary carrier requirements include: more bandwidth and greater transmission distance; better bandwidth utilization per wavelength; network visibility and manageability across subnetworks; smaller form factor, less power and lower cost; and preservation of legacy equipment.
Conventional technology, however, requires a very large number of devices to achieve the required rates and it does not provide support for future high data rate transport needs. Existing DWDM systems do not provide for adequate integration of the network components, and therefore, require a significant amount of space, which is at a premium in small central offices and other network locations.
The predominant problems with first-generation DWDM systems involve the inefficient use of wavelengths, because each service may require a dedicated wavelength. Furthermore, these solutions provide only simple transport of client signals (e.g., Optical Carrier level 48 (OC48), Gigabit Ethernet) without DWDM monitoring or client-specific monitoring. Second-generation DWDM systems use SONET/SDH (Synchronous Optical NETwork/Synchronous Digital Hierarchy) framing to address some of these problems, but still have shortcomings of their own. Some of these problems include: limited transparency; little to no support for strong forward error correction (FEC); inefficient transport of packet traffic (e.g. Ethernet); and a deep protocol stack that requires many chips and complex line card designs.
What is needed is a high-speed network and network components that are capable of performing at a level consistent with optical network systems and which efficiently support DWDM in a space-effective and cost-effective manner.